Surprising result of calculating speeds of two cars hitting a tree

I get the math and everything else, but there are a lot of real world assumptions here as well. Like the other driver decided to install something other than the cheapest brakes and most basic tires they could find. I typically gauge the other cars around me and what they are capable of in relation to what I’m driving. If the car in front of me is significantly better equipped then I’m going to leave enough room just in case.